1. Field of the Invention
The invention relates generally to the interconnect between the read/write circuitry and the read/write head in a magnetic recording hard disk drive (HDD), and more particularly to an interconnect for the read sensors in a two-dimensional magnetic recording (TDMR) HDD.
2. Description of the Related Art
In magnetic recording HDDs, the read/write head is formed on an air-bearing slider that rides on a thin film of air above the rotating disk. A mechanical suspension comprised of a flexure with a gimbal at its end connects the slider to the disk drive's actuator arm. The slider is attached to the gimbal that allows for slight movement on the air bearing as the disk rotates. A transmission line provides electrical connection from the read/write circuitry, typically in a read pre-amplifier/write driver module or chip, through a short flex cable and suspension to the read and write elements on the slider. A suspension that integrates the mechanical connection with the electrical connection is called an integrated lead suspension (ILS) that is connected between the flex cable and connection pads on the slider. A typical ILS is a generally flexible laminate of a conductive metal substrate like stainless steel, an insulating dielectric layer like polyimide, and electrically conductive copper lines or traces patterned on the dielectric layer. The transmission line for the signals from the write driver to the write head thus include electrically conductive lines on the flex cable and the ILS.
A proposed HDD technology that uses a read head with multiple read sensors is two-dimensional magnetic recording (TDMR). In TDMR, multiple read sensors that are located on a single read head access the same or adjacent data tracks to obtain signals that are processed jointly. This allows the data tracks to be placed closer together, resulting in an increase in areal data bit density. A structure with multiple stacked read sensors for TDMR is described in US 2013/0286502 A1. However, TDMR presents challenges in the design of the ILS because of interference or cross-talk between the multiple read sensor signal lines on the ILS.
What is needed is an ILS for a TDMR HDD that minimizes cross-talk between the read sensor signal lines.